• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

Naval Historical Society of Australia

Preserving Australia's Naval History

  • Events
  • Account
  • Members Area
  • Volunteer
  • Donate
  • Contact us
  • Show Search
  • 0 items
Hide Search
Menu
  • Home
  • Research
    • Where to start
      • Research – We can help!
      • Self help
      • Naval Service Records
      • Library
      • Related Maritime websites
    • Resources
      • Articles
      • Videos
      • On This Day
      • Podcasts
      • Australian Military Ship Losses
      • RAN events on a  Google Earth Map
      • RAN Vessels – Where are they now?
      • Related Maritime websites
    • Other
      • Newsletters: Call The Hands
      • Occasional Papers and Historical Booklets
      • Books
      • HMAS Shropshire
      • Book reviews
    • Close
  • Naval Heritage Sites
    • World Heritage Listings
      • Cockatoo Island
    • National Heritage Listings
      • HMAS Sydney II and the HSK Kormoran Shipwreck Sites
      • HMVS Cerberus
    • Commonwealth Heritage Listings
      • Garden Island NSW
      • HMAS Watson
      • HMAS Penguin
      • Spectacle Island Explosives Complex NSW
      • Chowder Bay Naval Facilities
      • Beecroft Peninsula NSW
      • Admiralty House, Garden and Fortifications
      • HMAS Cerberus
      • Naval Offices QLD
      • Garden Island WA
      • Royal Australian Naval College ACT
      • Royal Australian Naval Transmitting Station ACT
    • NSW Heritage Listings
      • HMAS Rushcutter
    • Close
  • Naval Art
  • Tours & Cruises
    • Navy in Sydney Harbour Cruise, East
    • Navy in Sydney Harbour Cruise, West
    • Anniversary Cruise: Sydney under Japanese Attack
    • Tour Bookings
    • Close
  • About us
    • About Us
      • What we do
      • Our People
      • Office Bearers
      • Become a volunteer
      • Our Goals and Strategy
    • Organisation
      • Victoria Chapter
      • WA Chapter
      • ACT Chapter
    • Close
  • Membership
  • Shop
  • Become a volunteer
  • Donate
You are here: Home / Article topics / Publications / Naval Historical Review / Garden Island Rangefinding

Garden Island Rangefinding

Haynes, Fred · Sep 24, 2018 · Print This Page

Author
Haynes, Fred
Subjects
Naval technology
Tags
Garden Island
RAN Ships
None noted.
Publication
September 2018 edition of the Naval Historical Review (all rights reserved)

Before the days of radar an array of optical rangefinders was an important feature of nearly all warships. In Royal Naval vessels, including those of the Dominions, these were mostly made by the Glasgow firm of Barr & Stroud and rangefinders fitted in RAN ships were returned to the makers for repairs and calibration. As this was time consuming and expensive a decision was made in the early 1920s to conduct future rangefinder maintenance and repairs locally at Garden Island Dockyard.

It was not until 1925 that a site for a repair shop was selected and built on the northern hill alongside the signal station with access by Hill Road past the dockyard residences. This site presented long and uninterrupted views down harbour.

Tradesmen, including a foreman with required expertise, were recruited in the United Kingdom, most likely poached from Barr & Stroud. As optical work had previously been conducted by the Dockyard on submarine periscopes there was some level of local experience already available. This existing work had been carried out in the electrical workshop near the dominant shear-leg crane.

The largest rangefinder then fitted to capital ships such as the battle-cruiser HMAS Australia was the FX3 which measured 22 feet (6.7 m) in length. To enable these large instruments to be repaired and calibrated a special jig was sent out by Bar & Stroud and fitted along the eastern side of the new hillside repair shop. This enabled the water tower on Dover Heights and other similar landmarks to be used for calibration, with Clark and Shark islands used for closer ranges. In 1930 a two storey addition to the original building was completed, enabling all optical and mechanical instruments in the RAN inventory to be repaired locally.

With the WWII development of radar, optical range-finding became obsolete. The last RAN ships capable of being fitted with rangefinders within their directions systems were the HMA Ships the DDGs Brisbane, Hobart and Perth. However, as weight restrictions to these particular ships were imposed by the incorporation of the Ikara ASW missile system, their rangefinders were not installed. Photographs of these DDGs show that the directors have blanking discs where the rangefinders should have protruded.

This just left the smaller one metre base rangefinders used by ships for navigational purposes. These smaller instruments required much closer targets for calibration which included the top of the staircase on the western side of the Dockyard Chapel and the northern end of the Finger Wharf at Woolloomooloo Bay. For longer ranges the closest of the twin flagstaffs on top of the Harbour Bridge was used.

With the construction of a new Weapons Building (No 79) in 1969 the optical workshop was sited on the top level of this building with a new periscope workshop on the level below.

This did not last long: with the further construction of a new Integrated Weapons Workshop along the western side of the Captain Cook Dock in 1987 the limited work on rangefinders continued here until the closure of the Optical and Periscope workshop in 2010. So ended 85 years of local technical support by Garden Island Dockyard for the maintenance of optical instruments.

 

Rangefinder taken from WWI battleship HMS Revenge          Imperial War Museum

 

Naval Historical Review, Naval technology Garden Island

Primary Sidebar

SUBSCRIBE

Sign up for our monthly e-newsletter.

  • This field is for validation purposes and should be left unchanged.

Categories

Latest Podcasts

  • The Fall of Singapore
  • HMAS Armidale
  • Napoleon, the Royal Navy and Me
  • The Case of the Unknown Sailor
  • Night of the midget subs — Sydney under attack

Links to other podcasts

Australian Naval History Podcasts
This podcast series examines Australia’s Naval history, featuring a variety of naval history experts from the Naval Studies Group and elsewhere.
Produced by the Naval Studies Group in conjunction with the Submarine Institute of Australia, the Australian Naval Institute, Naval Historical Society and the RAN Seapower Centre

Life on the Line Podcasts
Life on the Line tracks down Australian war veterans and records their stories.
These recordings can be accessed through Apple iTunes or for Android users, Stitcher.

Video Links

  • Australian War Memorial YouTube channel
  • Royal Australian Navy YouTube Channel
  • Research – We can help!
  • Naval Heritage Sites
  • Explore Naval Art
  • Dockyard Heritage Tour
  • About us
  • Shop
  • Events
  • Members Area
  • Volunteer
  • Donate
  • Contact us

Follow us

  • Facebook
  • YouTube
  • Members Area
  • Privacy Policy

Naval Historical Society of Australia Inc. Copyright © 2025